SphereLight

An intrinsic light that emits light outwards from a sphere. This light is one-sided, so no light is emitted “inside” the sphere. This light can be used as a zero-radius “point light” if treatAsPoint is true, and the renderer being used supports zero-area lights.

Use SphereLights to simulate point and spherical shaped light sources, like light bulbs and headlamps.

The following simple example has a SphereLight positioned near a Sphere and Cube, with a radius of 0.8.

#usda 1.0
(
    upAxis = "Y"
)

def Scope "Lights"
{
    def SphereLight "Light1"
    {
        float inputs:radius = 0.8

        color3f inputs:color = (1, 1, 1)
        float inputs:intensity = 20.0
        double3 xformOp:translate = (4, 0, 1)
        uniform token[] xformOpOrder = ["xformOp:translate"]
    }
}

def Xform "TestGeom"
{
    def Sphere "Sphere1"
    {
        token purpose = "render"
        color3f[] primvars:displayColor = [(1, 1, 1)] (
            interpolation = "constant"
        )    
        double3 xformOp:translate = (0, 0, -2)
        uniform token[] xformOpOrder = ["xformOp:translate"]          
    }

    def Cube "Cube"
    {
        token purpose = "render"
        color3f[] primvars:displayColor = [(1, 1, 1)] (
            interpolation = "constant"
        )    
        double size = 8
        double3 xformOp:translate = (0, 0, -8)
        uniform token[] xformOpOrder = ["xformOp:translate"]          
    }
}

Example RenderMan output for this layer (compare with the output for the DiskLight example, which has a similar configuration):

Properties

inputs:radius

USD type: float

Fallback value: 0.5

Radius of the sphere.

light:shaderId

USD type: token

Fallback value: SphereLight

The shader ID for a SphereLight. USD will also register a Sdr shader node with a “SphereLight” identifier and the source type “USD” to correspond to the light’s inputs

treatAsPoint

USD type: bool

Fallback value: False

This is used as a hint to renderers that this light can be treated as a “point light”, effectively a zero-radius sphere. This is useful for renderers that support non-area lighting. Renderers that only support area lights will ignore this attribute.

Inherited Properties (Boundable)

extent

USD type: float3[]

Inherited Properties (Xformable)

xformOpOrder

USD type: token[]

Inherited Properties (Imageable)

proxyPrim

USD type: rel (relationship)

purpose

USD type: token

Fallback value: default

visibility

USD type: token

Fallback value: inherited